미니스폿 Mini Spot Welder for 18650 battery - South Korea

I am interested in DIY.
Many people use 18650 batteries, but spot welding is difficult.
It is very useful if you make a battery pack with 18650.
There is a performance limit. This is not an industrial use.
However, I think this is the smallest spot welder.
It can only be held in one hand, and the battery used is also very small.
I suggest using an RC battery as a power source for spot welding.
The RC battery is very small.
Other spot welders use automotive batteries.
This may be called a mobile spot welder.
The production cost is also very low.
I set up a circuit on my blog and refer to it.
blog.naver.com/...
I do not speak English very well, so please understand that I wrote in Korean.
I made Spot Welder for battery connection (18650, etc)
Connection meteral is 0.1~0.15T Nickel plate.
Using RC Battery - 30c, 5000mah, 3s (12.6v)